US3945733A - Mechanical pencil - Google Patents

Mechanical pencil Download PDF

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Publication number
US3945733A
US3945733A US05/460,906 US46090674A US3945733A US 3945733 A US3945733 A US 3945733A US 46090674 A US46090674 A US 46090674A US 3945733 A US3945733 A US 3945733A
Authority
US
United States
Prior art keywords
annulus
half shells
collet
housing
mechanical pencil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05/460,906
Other languages
English (en)
Inventor
Guenter Edel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Faber Castell AG
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US3945733A publication Critical patent/US3945733A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores
    • B43K21/20—Writing-core feeding mechanisms with stepwise feed of writing-cores with writing-cores automatically replaced from magazines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/04—Writing-core feeding mechanisms with the writing-cores brought into position by gravity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/16—Writing-core feeding mechanisms with stepwise feed of writing-cores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K21/00—Propelling pencils
    • B43K21/02—Writing-core feeding mechanisms
    • B43K21/22—Writing-cores gripping means, e.g. chucks

Definitions

  • the present invention is directed to a mechanical pencil of the collet-action type whereby a shiftable lead is carried within a collet member and this collet member is maintained in a gripping relationship by the effect of a compression spring and is movable in opposition to the bias of the spring to advance the lead outward from the collet and, more particularly, to the design of such a collet member.
  • FIGS. 4 through 7 of the pending U.S. application, Ser. No. 423,476 A sample embodiment of a mechanical pencil of the above type is shown in FIGS. 4 through 7 of the pending U.S. application, Ser. No. 423,476.
  • This application describes a mechanical pencil with an outer housing having a bore formed along its axis.
  • a collet member is formed by a pair of identically configured mating shells which are maintained in a fixed relation with respect to one another by a cap at one end thereof.
  • the collet member is placed inside the housing bore and the cap extends beyond the housing. It can be depressed against the action of a compression spring from the outside of the housing.
  • the depression and the simultaneous compression of the spring releases an annulus which was forced against a flared end portion of the collet member by the action of the spring, and permits the advancement of the lead.
  • the compression spring pulls the collet member into the annulus. Thereby, gripping forces are exerted onto the lead which are sufficient
  • the collet member is inserted into the annulus by axially displacing the collet halfs with respect to one another in such a way that a reduced portion of the collet member mates with the flared portion of this collet member during the insertion process. It is thereby required that both the annulus and the half shells are somewhat elastic, which makes if difficult to provide materials having the requisite sliding properties on the outside and gripping properties on the lead guiding tube side of the collet member as well as good durability of the annulus and the collet member. In addition, the assembly of two deformable members may be quite difficult.
  • each collet half has a partially reduced diameter such that most of the diameter of the outer flared portions is still larger than the boring of the annulus in a part thereof.
  • this reduced diameter portion of the collet halfs permits the safe gripping of the lead, and simultaneously, prevents an inadvertent removal of the annulus under the effect of the compression spring by an exact calculation of the diameter reduction such that the collet member and the annulus have mating outlines during their assembly.
  • glass-fiber reinforced plastics such as polystyrene, polyamide or so-called ABS materials (acrylic butadiene styrene) have been found to be suited best for the collet member.
  • Metals or polyacidal resins have proven to be particularly advantageous for the production of the annulus. Both of these materials can be selected in view of their strength and sliding properties as well as their surface condition. The most advantageous materials have little cold flow and great continuous strength, even if ambient temperature conditions fluctuate greatly during their use. As this has been the case in metal collet members, where a particularly springy steel has been selected, it is now possible to select a plastic material with good springy properties within a limited margin.
  • FIG. 1 is a longitudinal section through a complete mechanical pencil and its advance system, showing the collet member and the annulus in their assembled positions,
  • FIG. 2 is a front view of the two half shells of the collet member and the annulus, after they have been inserted, whereby the lead 48 is in its position,
  • FIG. 3 is a partial section through the annulus and the upper half of the collet member in its final position, while the lower half of the collet member has not yet been inserted and is axially displaced with respect to the upper half,
  • FIG. 4 is a longitudinal section through the arrangement of FIG. 3, taken along line IV--IV of FIG. 3,
  • FIG. 5 is a longitudinal section through an arrangement as in FIG. 2, taken along line V--V, whereby the lead had been previously removed,
  • FIG. 6 is a front view of a particularly advantageous embodiment according to this invention, showing the annulus and the upper half shell, before its insertion into the annulus, and
  • FIG. 7 is a front view of the annulus and both collet halfs, during the insertion of the second and lower collet half.
  • FIG. 1 illustrates a completely mounted mechanical lead pencil according to the invention comprising an outer housing 10 with the axial boring 12.
  • One of the end portions 14 of the outer housing 10 has been provided with a thread 16, while forming a shoulder 18.
  • a tip member 20 comprises a mating thread portion 22 and an axial bore 24, the diameter of which is reduced twice, while forming shoulders 26 and 28.
  • the bore 24 of the tip member 20 is conically reduced and provided with elastic members 30.
  • One half shell 32 of the collet member is placed within the outer housing 10, and it comprises an axial bore 34 serving as lead guiding tube.
  • the outer diameter of this half shell 32 is reduced to form a shoulder 36 serving as bearing for compression spring 38.
  • the other bearing for this compression spring 38 is formed by the mounting ring 40 which is held by the shoulder 18 of the outer housing 10 and the end portion of the tip member 20.
  • the annulus 42 rests against the other side of this mounting ring 40 inside the axial bore 24 of the tip member 20.
  • the collet half 32 has a conically outwardly flared end portion 44 with an outer diameter which is larger than the inner diameter of the annulus 42.
  • a shoulder 46 formed by the collet half provides a reduced inner diameter of the lead guide tube 34 in the area forming the gripping surfaces for the lead 48.
  • the opposite end 50 of the collet half 32 has a reduced outer diameter and serves to receive an end closure cap 52 which extends beyond the housing 10.
  • end closure cap 52 When end closure cap 52 is depressed, spring 38 is compressed, permitting the flared end portion 44 of the collet half shell 32 to emerge from the annulus 42, thereby advancing the lead 48.
  • the elastic members 30 maintain the lead 48 in the advanced position, while the flared outer portion 44 retracts into the annulus 42 after the release of the end closure cap 52.
  • FIGS. 4 and 5 show how the compression spring 38, the mounting ring 40 and the annulus 42 are plugged into the two collet halves 32 which are axially displaced with respect to one another.
  • FIG. 3 illustrates an embodiment, whereby the diameter of the flared portion 44 has been reduced at 54 as much as required for the plugging process, while FIGS. 6 and 7 show an embodiment where the reduction 56 is designed to reduce the outer diameter of the flared portion 44 of the collet half 32 as little as possible.
  • FIGS. 2 and 3 has proven quite satisfactory for pencils whose lead 48 is not removed. However, it may be desirable to take precautionary measures such that the pressure of the compression spring 38 can not pull the flared end 44 of the collet member 32 through the annulus 42, even when the lead 48 is removed whereby the slot 58 closes.
  • the reduction 56 has been adapted to the shape of the annulus 42 by exact mathematical calculations, whereby the outer diameter of the flared portion has been maintained as large as possible over as great a portion of the outer circumference as possible.
  • the maximum distance between the reduced diameter portions here corresponds exactly to the inner diameter of the annulus. This embodiment allows the easiest insertion into the annulus which is possible, while preventing that the collet member is pulled through the annulus 42 by the action of the compression spring 38.

Landscapes

  • Mechanical Pencils And Projecting And Retracting Systems Therefor, And Multi-System Writing Instruments (AREA)
US05/460,906 1973-10-12 1974-04-15 Mechanical pencil Expired - Lifetime US3945733A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT872573A ATA872573A (de) 1973-10-12 1973-10-12 Fullminenstift mit verschiebbarer mine
OE8725/73 1973-10-12

Publications (1)

Publication Number Publication Date
US3945733A true US3945733A (en) 1976-03-23

Family

ID=3608019

Family Applications (1)

Application Number Title Priority Date Filing Date
US05/460,906 Expired - Lifetime US3945733A (en) 1973-10-12 1974-04-15 Mechanical pencil

Country Status (4)

Country Link
US (1) US3945733A (enrdf_load_stackoverflow)
JP (1) JPS5634477B2 (enrdf_load_stackoverflow)
AT (1) ATA872573A (enrdf_load_stackoverflow)
DE (1) DE2447234C3 (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2737538A1 (de) * 1976-08-20 1978-02-23 Pentel Kk Druckstift
FR2362012A1 (fr) * 1976-08-20 1978-03-17 Pentel Kk Portemine a mandrin et magasin tubulaire
US4153379A (en) * 1977-01-25 1979-05-08 Chao Wen Kuei Knock-out type automatic pencil
US4180339A (en) * 1977-06-29 1979-12-25 A. W. Faber-Castell Mechanical pencil with automatic lead feed
US4251163A (en) * 1979-03-21 1981-02-17 Chao Wen Kuei Knock-out type automatic pencil
US4896981A (en) * 1988-07-05 1990-01-30 Mosu Pencil Corporation Automatic pencil
US5555602A (en) * 1994-12-14 1996-09-17 Leamond; William T. Eraser assembly
US5702193A (en) * 1994-07-22 1997-12-30 Kotobuki & Co.,Ltd. Side knock type mechanical pencil
US6039485A (en) * 1997-05-13 2000-03-21 Kotobuki & Co., Ltd. Double-chuck mechanical pencil
US20060165471A1 (en) * 2005-01-24 2006-07-27 Antonio Fernandez Fernandez Casing for bar-shaped cosmetic products
US20190135023A1 (en) * 2017-11-07 2019-05-09 Chadwick Parker Refill friendly pen body

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5184649U (enrdf_load_stackoverflow) * 1974-12-27 1976-07-07
JPS51152438U (enrdf_load_stackoverflow) * 1975-05-30 1976-12-06
JPS52160445U (enrdf_load_stackoverflow) * 1976-05-29 1977-12-06
JPS5354138U (enrdf_load_stackoverflow) * 1976-10-08 1978-05-10
DE2649871C3 (de) * 1976-10-29 1980-01-10 Fa. J.S. Staedtler, 8500 Nuernberg Druckbleistift
JPS5445632U (enrdf_load_stackoverflow) * 1977-09-05 1979-03-29
JPS5455436U (enrdf_load_stackoverflow) * 1977-09-27 1979-04-17
DE2826350C2 (de) * 1978-06-16 1986-11-27 A.W. Faber-Castell Unternehmensverwaltung GmbH & Co, 8504 Stein Vorrichtung zur Montage einer Spannzange in den Schaft eines Füllminenstiftes
JPS5669486U (enrdf_load_stackoverflow) * 1979-10-30 1981-06-09
DE3906346A1 (de) * 1989-03-01 1990-09-06 Staedtler Fa J S Klemmzange fuer fuellminenstifte
JP6286269B2 (ja) * 2014-04-17 2018-02-28 株式会社パイロットコーポレーション シャープペンシル

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2319823A (en) * 1942-05-25 1943-05-25 Eversharp Inc Mechanical pencil
FR1103083A (fr) * 1953-04-21 1955-10-28 Caran D Ache Crayons Porte-mine

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2319823A (en) * 1942-05-25 1943-05-25 Eversharp Inc Mechanical pencil
FR1103083A (fr) * 1953-04-21 1955-10-28 Caran D Ache Crayons Porte-mine

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2737538A1 (de) * 1976-08-20 1978-02-23 Pentel Kk Druckstift
FR2362012A1 (fr) * 1976-08-20 1978-03-17 Pentel Kk Portemine a mandrin et magasin tubulaire
US4140408A (en) * 1976-08-20 1979-02-20 Pentel Kabushiki Kaisha Push type mechanical pencil
DE2737538C2 (de) * 1976-08-20 1986-02-06 Pentel K.K., Tokio/Tokyo Druckstift
US4153379A (en) * 1977-01-25 1979-05-08 Chao Wen Kuei Knock-out type automatic pencil
US4180339A (en) * 1977-06-29 1979-12-25 A. W. Faber-Castell Mechanical pencil with automatic lead feed
US4251163A (en) * 1979-03-21 1981-02-17 Chao Wen Kuei Knock-out type automatic pencil
US4896981A (en) * 1988-07-05 1990-01-30 Mosu Pencil Corporation Automatic pencil
US6210058B1 (en) 1994-07-22 2001-04-03 Kotobuki & Co., Ltd. Side knock type mechanical pencil
US5702193A (en) * 1994-07-22 1997-12-30 Kotobuki & Co.,Ltd. Side knock type mechanical pencil
US6099182A (en) * 1994-07-22 2000-08-08 Kotobuki & Co., Ltd. Side knock-type mechanical pencil
US5555602A (en) * 1994-12-14 1996-09-17 Leamond; William T. Eraser assembly
US6039485A (en) * 1997-05-13 2000-03-21 Kotobuki & Co., Ltd. Double-chuck mechanical pencil
US6379067B2 (en) 1997-05-13 2002-04-30 Kotobuki & Co., Ltd. Double-chuck mechanical pencil
US20060165471A1 (en) * 2005-01-24 2006-07-27 Antonio Fernandez Fernandez Casing for bar-shaped cosmetic products
US20190135023A1 (en) * 2017-11-07 2019-05-09 Chadwick Parker Refill friendly pen body
US10836203B2 (en) * 2017-11-07 2020-11-17 Chadwick Parker Refill friendly pen body

Also Published As

Publication number Publication date
DE2447234C3 (de) 1980-10-02
DE2447234B2 (de) 1980-02-07
ATA872573A (de) 1976-08-15
JPS5078418A (enrdf_load_stackoverflow) 1975-06-26
DE2447234A1 (de) 1975-04-17
JPS5634477B2 (enrdf_load_stackoverflow) 1981-08-11

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